1. Technical Field
The present invention relates to the actuation mechanism of manipulator for maximizing performance such as velocity and force by moving the forcing-points which produce torque.
2. Background Art
Robots are being used over a variety of industrial areas. In addition to industrial robots, a remotely-controlled robot with multipurpose and a humanoid robot which has as high degree of freedom (hereinafter, referred to as “DOF”) as being capable of conducting various work in lieu of human is in demand and the research and development thereof are actively conducted recently.
In order to embody the various motion of a robot, a manipulator called a multi-joint arm including a plurality of articulated links joined together and actuators are commonly used. The actuators transform the energy into actual movement of the manipulator.
Redundant actuation mechanism is the mechanism with lower DOF than the number of actuators. While more difficult to control, larger and heavier than non-redundant mechanism, the redundant actuation mechanism is advantageous in several aspects such as avoidance of kinematical singularity, overcoming limit of velocity and input velocity, lessening impact force in contacting outer environment and avoidance of obstacle. The above-mentioned characteristics can be achieved by obtaining optimal solution from the given application purpose and environment.
As prior researches regarding to the redundant actuation mechanism, there are “Performance Analysis and Optimal Actuator Sizing for Anthropomorphic Robot Modules with Redundant Actuation” (The Korean Society of Mechanical Engineer, Vol. 19, No 1, pp. 181-192, 1995) which shows the performance improvement of a redundant actuation mechanism by comparing with a non-redundant actuation mechanism in terms of maximum load capacity, maximum velocity and maximum acceleration at an end-operator and “Operational quality analysis of parallel manipulators with actuation redundancy” (IEEE International Conference on Robotics and Automation, pp. 2651-2656, 1997) regarding the performance improvement of a manipulator by redundant actuation.
As further prior research regarding to distribution actuation mechanism, there are “A five-bar finger mechanism involving redundant actuators: Analysis and its applications” (IEEE Transactions on Robotics and Automation, Vol. 15, No. 6, pp. 1001-1010, 1999) regarding the effect to the working performance by the location of actuators and the number of used actuators in force distribution, “Load Distribution using Weighted Pseudoinverse Matrix in Redundant Actuation” (The Korean Society of Mechanical Engineer, 2002) regarding the force-distribution-method of a redundant actuation system by use of pseudoinverse matrix in 5-axis finger mechanism of the redundant actuation, and “Torque Distribution Control of 3RRR Redundant Parallel Robot” (Korean Journal of Precision Engineering and Manufacturing, Vol. 25, No. 2, pp. 72-79, 2008) regarding lowering maximum actuating torque by effectively distributing actuation input.